package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.TimeoutUtils;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock{

    //key值
    private String name;

    private StringRedisTemplate stringRedisTemplate;

    public SimpleRedisLock( String name,StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
        this.name = name;
    }

    private static final String KEY_PREFIX = "lock:";

    private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-";

    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT  = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }

    @Override
    public boolean tryLock(long timeoutSec) {
        
        //获取线程标识
        String threadId = ID_PREFIX + Thread.currentThread().getId();

        Boolean success = stringRedisTemplate.opsForValue().
                setIfAbsent(KEY_PREFIX + name,threadId, timeoutSec, TimeUnit.SECONDS);

        //自动拆箱 null会被拆箱成空指针
        return Boolean.TRUE.equals(success);
    }

//    @Override
//    public void unlock() {
//
//        //获取线程标识
//        String threadId = ID_PREFIX + Thread.currentThread().getId();
//
//        //Redis中的id 防止修改的是其他人的锁
//        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
//
//        if(threadId.equals(id)) {
//            //释放锁
//            stringRedisTemplate.delete(KEY_PREFIX + name);
//        }
//    }

    //调用脚本 一行代码lua脚本 保持原子性
    public void unlock() {
        stringRedisTemplate.execute(UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name),
                ID_PREFIX + Thread.currentThread().getId() );
    }
}
